基于人工磁导体表面的低剖面Fabry-Perot谐振腔天线设计

Design of Low-Profile Fabry-Perot Cavity Antenna Based on Artificial Magnetic Conductor

该文基于人工磁导体表面(Artificial Magnetic Conductor,AMC)设计了一款工作在7 GHz的新型低剖面Fabry-Perot谐振腔天线.该天线采用带金属接地板的矩形微带贴片天线作为初级馈源,由同轴探针进行馈电.以单层双面印制AMC表面作为天线的部分反射层,所设计AMC表面共包含8×8个均匀阵列单元,单元上层为带有方环的方形贴片,下层为菱形贴片.通过分析不同结构参数对AMC散射特性的影响,确定AMC反射相位为-25°,使得腔体的剖面高度降低至约9.2 mm(0.215λ,λ为7 GHz自由空间波长).制作了天线实物并进行测量,结果表明,天线阻抗带宽(S11<-10 dB)为14%(7 GHz~8.5 GHz),增益达到13.8 dBi,旁瓣水平低至-21.3 dB,表明该天线在保证低剖面同时仍具有良好的辐射性能.

In this paper,a novel low-profile Fabry-Perot cavity antenna is designed based on the Artificial Magnetic Conductor(AMC)which works at 7 GHz.A rectangular microstrip patch antenna with a metal ground plane is utilized as the primary feed source,and it is fed by a coaxial probe.A single-layer double-sided printed AMC surface is used as the partially reflective surface of the antenna.The proposed AMC surface consists of elements,each element is composed of three layers.The upper layer consists of a square patch and a square ring,and the lower layer consists of a diamond-shaped patch.By analyzing the influences of different structural parameters on the reflection characteristics of the AMC element,the reflection phase is fixed to-25°,so that the profile height of the cavity is reduced to about 9.2 mm(0.215λ,λ-the wavelength in free space at 7 GHz).A prototype antenna has been fabricated and tested.The results show that the impedance bandwidth of the antenna(|S_(11)|<-10 dB)is 14%(7 GHz~8.5 GHz).And the gain of the antenna reaches up to 13.8 dBi,and the side lobe level is lower than-21.3 dB.The results indicate that the antenna exhibits good radiation performance with a low profile.